PDF(Pubmed)
Abstract：
Drylands are unique among terrestrial ecosystems in that they have a significant proportion of primary production facilitated by non-vascular plants such as colonial cyanobacteria, moss, and lichens, i.e., biocrusts, which occur on and in the surface soil. Biocrusts inhabit all continents, including Antarctica, an increasingly dynamic continent on the precipice of change. Here, we describe in-situ field surveying and sampling, remote sensing, and modeling approaches to assess the habitat suitability of biocrusts in the Lake Fryxell basin of Taylor Valley, Antarctica, which is the main site of the McMurdo Dry Valleys Long-Term Ecological Research Program. Soils suitable for the development of biocrusts are typically wetter, less alkaline, and less saline compared to unvegetated soils. Using random forest models, we show that gravimetric water content, electrical conductivity, and snow frequency are the top predictors of biocrust presence and biomass. Areas most suitable for the growth of dense biocrusts are soils associated with seasonal snow patches. Using geospatial data to extrapolate our habitat suitability model to the whole basin predicts that biocrusts are present in 2.7 × 105 m2 and contain 11-72 Mg of aboveground carbon, based on the 90% probability of occurrence. Our study illustrates the synergistic effect of combining field and remote sensing data for understanding the distribution and biomass of biocrusts, a foundational community in the carbon balance of this region. Extreme weather events and changing climate conditions in this region, especially those influencing snow accumulation and persistence, could have significant effects on the future distribution and abundance of biocrusts and therefore soil organic carbon storage in the McMurdo Dry Valleys.
摘要：
旱地在陆地生态系统中是独一无二的，因为它们有很大一部分初级生产是由殖民地蓝细菌等非维管植物促进的，苔藓,还有地衣,即，生物锈蚀，发生在表层土壤上和表层土壤中。生物锈蚀遍布各大洲，包括南极洲,在变化的悬崖上日益活跃的大陆。这里,我们描述了现场测量和采样，遥感,和建模方法来评估泰勒谷弗莱克塞尔湖盆地生物锈病的生境适宜性，南极洲,这是麦克默多干谷长期生态研究计划的主要地点。适合生物锈蚀发育的土壤通常较湿润，碱性较低，与无植被的土壤相比，盐分较少。使用随机森林模型，我们表明重量含水量，电导率，降雪频率是生物存在和生物量的主要预测因子。最适合生长密集生物锈蚀的区域是与季节性积雪有关的土壤。使用地理空间数据将我们的栖息地适宜性模型推断到整个盆地，预测生物锈蚀存在于2.7×105m2中，含有11-72Mg的地上碳，基于90%的发生概率。我们的研究说明了结合野外和遥感数据对了解生物锈病的分布和生物量的协同作用，该地区碳平衡的基础社区。极端天气事件和该地区不断变化的气候条件，尤其是那些影响积雪和持久性的因素，可能会对McMurdo干谷中生物锈病的未来分布和丰度以及土壤有机碳储量产生重大影响。
